During the Ice Age (Pleistocene Epoch) the Tri-Cities was repeatedly inundated by some of the world’s largest fresh water floods. Some of these floods exceeded ten times the flow rate of all the rivers of the world combined. The floods forever changed the face of the northwest from Missoula, Montana to Astoria, Oregon, and are the subject of a new Ice Age Floods National Geologic Trail. These floods also had profound impacts on Pleistocene mammals that lived in the path of the floods. This presentation will provide an overview of the floods and ongoing efforts to examine their impacts on Columbian Mammoths (the official Washington State Fossil).